This invention relates to microorganisms useful for providing amides from nitrites and processes for producing amide compounds by using the microorganisms.
Amides and derivatives thereof are useful compounds that are utilized in various fields. For example, 2-hydroxy-4-butyric acid obtained by hydrolyzing 2-hydroxy-4-methylthiobutyramide is utilized as an additive to feed for supplementing the lack of amino acids containing sulfur in rearing livestock, particularly poultry.
In recent years, processes for producing amides from nitrites by utilizing the action of microorganisms or enzymes extracted from microorganisms are proposed. As the microorganisms, there are presented, for example, microorganisms belonging to the genus Bacillus, the genus Bacteridium, the genus Micrococcus and the genus Brevibacterium (Japanese Patent Publication No. 21519/1987 (JP-B-62-21519)), microorganisms belonging to the genus Corynebacterium and the genus Nocardia (Japanese Patent Publication No. 17918/1981 (JP-B-56-17918)), microorganisms belonging to the genus Pseudomonas (Japanese Patent Publication No. 37951/1984 (JP-B-59-37951)), microorganisms belonging to the genus Rhodococcus, the genus Arthrobacter and the genus Microbacterium (Japanese Patent Application Laid-Open No. 162193/1986 (JP-A-61-162193)), microorganisms belonging to the genus Fusarium (Japanese Patent Application Laid-Open No. 86889/1989 (JP-A-64-86889)), microorganisms belonging to the genus Acinetobacter (Japanese Patent Application Laid-Open No.154692/1990 (JP-A-2-154692)).
Moreover, as the processes for forming amides from nitriles, there are known, for example, a process using a strain of the genus Xanthobacter (Japanese Patent Application Laid-Open No. 154692/1990 (JP-A-2-154692)), a process using a strain of the genus Klebsiella (Arch. Microbiology, Vol. 156, pages 231-238 (1991)), a process using a strain of the genus Streptomyces, the genus Serratia, the genus Erwinia, the genus Tukamurella, the genus Gordona, the genus Morganella, the genus Proteus, the genus Enterobacter, the genus Microascucs, the genus Camdida or the genus Pantoea (Japanese Patent Application Laid-Open No. 15384/1993 (JP-A-5-15384)), a process using a strain of the genus Citrobacter (Japanese Patent Application Laid-Open No. 30983/1993 (JP-A-5-30983)), a process using a strain of the genus Rhizobium (Japanese Patent Application Laid-Open No. 236977/1993 (JP-A-5-236977)), and a process using a strain of the genus Agrobacterium (Japanese Patent Application Laid-Open No. 14786/1994 (JP-A-6-14786)). However, inanyprocess described above, productivity is low and it is difficult to industrially produce an amide with efficiency.
Japanese Patent Application Laid-Open No. 40899/1992 (JP-A-4-40899) discloses, in a process for producing 2-hydroxy-4-methylthiobutyramide from 2-hydroxy-4-methylthiobutanenitrile, the use of a strain of microorganism belonging to the genus Rhodococcus, the genus Coynebacterium, the genus Pseudomonas, the genus Arthrobacter or the genus Alcaligenes. According to the Examples in this literature, there is described that 2-hydroxy-4-methylthiobutyramide can be produced, at the maximum, a molar concentration of 253 mM (concentration: 37.7 g/L, yield: 63%) from 400 mM of 2-hydroxy-4-methylthiobutanenitrile by the reaction, using Rhodococcus rhodochrous ATCC 33278, for 40 hours. In this process, however the amide-producing rate is as much low as 1 g/L.hr or lower, and it is unable to raise the productivity and economical efficiency.
Further, WO98/32872 discloses the production of 2-hydroxy-4-methylthiobutyramide from 2-hydroxy-4-methylthiobutanenitrile by using strains 52 and 56 wt of the genus Rhodococcus and its detailed production process. In this process, however, the specific activity of the cell (mycobiont) within one hour from the beginning of the reaction is as much low as 100 xcexcmol/min.g-drycell per 1 g of dried cell (mycobiont), therefore unable to raise the productive efficiency and economical efficiency.
Usually, the more complicated the structure of a nitrile becomes, the lower the hydration activity and the conversion efficiency of nitriles to amides of microorganisms are. Thus, it is difficult to produce amides from nitriles having intricate structures with higher efficiency and at a higher rate.
It is, therefore, an object of the present invention to provide a novel microorganism useful in producing an amide from a nitrile, efficiently and at a high production rate, in which the amide corresponds to the nitrile, and a process for producing an amide compound using the microorganism.
It is another object of the present invention to provide a novel microorganism capable of producing an amide from a nitrile at a high production rate, even if the nitrile has a complicated structure, and a process for producing an amide compound using the microorganism.
The present inventors did much investigation to accomplish the above objects and, as a result, found a novel species of microorganism having an ability to produce an amide compound from a nitrile with high productivity. The present invention has been accomplished based on the above findings.
Thus, the microorganism of the present invention is a novel species of microorganism having a base sequence shown by sequence No.1 or sequence No.2 of the sequence listing as a base sequence of 16S rRNA gene. The microorganism usually has an ability to convert a nitrile to an amide. The microorganism may be a strain of microorganism belonging to the genus Rhodococcus, such as Rhodococcus sp. Cr4 strain (FERM BP-6596) or Rhodococcus sp. Am8 strain (FERM BP-6595). Moreover, the present invention includes a process for producing an amide compound comprising allowing the microorganism or a preparation derived therefrom to act upon a nitrile thereby to convert the nitrile to an amide. The nitrile may be a cyanohydrin such as 2-hydroxy-4-methylthiobutanenitrile.